During intraocular or endoscopic surgery, a surgeon may need to alter both the intensity and the direction of light in order to better visualize the surgical field. Conventional light sources often work similar to a flashlight, with a directed beam that focuses light directly on a specific area. This direct illumination prevents the surgeon from fully visualizing any texture or surface irregularities. Consequently, surgeons often employ special stains or dyes to help visualize the surgical field. For example, during vitreoretinal surgery for an epiretinal membrane, direct illumination of the membrane is often inadequate to visualize the tissue, so vital stains may be used to increase visibility of the tissue.
Handheld lights that provide direct illumination typically have a field of illumination of about 50 to 80 degrees. This direct illumination fails to highlight the texture of a surface. Further, reducing the distance between the light and the surface of the retina increases the risk of phototoxicity to retinal photoreceptors. Wide-field chandelier lighting systems typically have a 100 degree field of illumination, but are placed at a fixed distance from the retina and therefore cannot provide side illumination to highlight surface texture. Further, chandeliers cast shadows when working instruments are placed in front of them, and are also prone to creating glare during air-fluid exchanges such as those required during vitrectomy. Further, chandeliers are often incapable of homogenously illuminating the entire eye, and often need to be repositioned during surgery. Further, the tips of chandelier lights or probes are prone to melting if they come into contact with blood or uveal tissue. Existing fiber optic illumination systems provide direct or wide-field illumination only. A need exists for improved surgical lighting system, especially those effective for visualizing the surface details of ocular tissue.